1. Field of Invention
The present invention relates to a method for reducing fluid resistance including frictional resistance, viscous pressure resistance and similar resistances and propelling (adding pressure), and typical application devices realized in multi-fields.
2. Description of Related Arts
In the long term search for fluid resistance reducing methods, attention is only focused on and limited to the shape, i.e., an exploration of streamlines of objects. Air resistance reduction designs of high-speed trains, missiles, automobiles and etc. still remain on this stage. After the establishment of boundary layer theory and several years' development, conventional resistance reducing methods are divided into four categories based on different ways of reducing viscous resistance. The first category includes methods of partially changing the fluid near boundaries, such as hovercraft technology and air lubrication technology. The first category has a considerable potential to reduce resistance. However, practical technology and technological measures of replacing viscous fluids having quite different viscosity and specific gravity on all the boundaries remain to be completely solved, and thus promotion thereof is difficult. The first category is mainly applied in transportation and mechanical engineering. The second category changes velocity distribution on the laminar boundary layer by changing and controlling temperatures of the boundary layer or through suctions so as to reduce viscous resistance. The second category is usually applied in the field of external flow such as aviation, as discussed with details in many monographs, and has limited effects of reducing resistance. The third category reduces resistance through injecting polymer dilute solution in mural areas and can be applied in fluid resistance reduction such as crude oil and water. However, high polymers are expensive and readily ineffective under shearing forces. Resistance reduction effects thereof are limited. The fourth category uses proper boundary materials such as elastic materials to form flexible and smooth boundary which tends to produce dynamic response and vibrate with fluctuation of T-S wave on the laminar boundary layer. The fourth category derives from bionics, but has limited resistance reduction effects. Researches of reducing shape resistance mainly remain on the exploration of the streamlines of objects and also include some other technologies. For example, a channel connecting the head and the tail is arranged in the internal of the object to be resistance-reduced, in such a manner that the fluid moves from the leading end to the trailing end through the channel and pressure different between the leading end and the trailing end is reduced to further reduce viscous pressure resistance, similar to water jet propulsion technology; however, shape resistance of the entrance of the channel and the fluid frictional resistance on the internal surface are relatively large so as to impact the effects of reducing resistance and limits practically applied places. Another example allows boundary face of an object to move with fluid, which is early discovered and has been proved by visual experiments. However, this technology is nearly forgotten because of difficulty in realization and practical application and technical solutions thereof have limited effects of reducing resistance. These conventional resistance reducing methods are discussed in various teaching materials and monographs about resistance reduction mechanics; various conventional propulsion devices (with pumping devices) are mainly for providing propelling forces or pressure and have nothing to do with the fluid resistance reduction.
The inventor discloses “method for reducing fluid resistance and apparatus for the same” in an international application, PCT/CN2006/001825, filed 2006. The inventor also got a Chinese patent of ZL200610106732.4 having an approximately same invention in a manner of resistance reducing propulsion device. The method for reducing resistance includes providing at least one level of movable walls in turn on surface of the object to be resistance-reduced, in such a manner that the boundary face is separated with the object surface and moves with the fluid, wherein the one level of movable walls comprises at least one layer wall; replacing fluids near the surface through manual intervention to produce stratified fluids moving orderly in certain manner, wherein each layer respectively moves at a certain relative velocity, in such a manner that the boundary face reduces the relative velocity to the fluid through relatively small moving resistance and even moves faster than the fluid so as to reduce even eliminate the fluid resistance. For the external flow manner and some internal flow manner, multiple layers of movable walls are arranged on the surface of the internal channel connecting the leading end and the trailing end of the object and at the two sides of the object. When a driving device is used to apply driving forces on the movable boundary face to produce a moving velocity of the boundary face larger than the fluid velocity or to apply driving forces on the fluid, propelling forces emerge while negative pressure emerges in the front part and positive pressure emerges in the back part, in such a manner that a part of viscous resistance is counteracted and fluid frictional resistance disappears, even the shape resistance can be reduced in the condition of the external flow manner. The invention discloses a method that the fluid near the boundary layer moves stratifiedly and orderly through manual intervention to reduce the fluid frictional resistance and the complete typical device for applying manual intervention on the fluid movement. The complete typical device mainly simulates a belt conveyer which supports moving belt with supporting rollers, uses many rolling cylinders to support various film structures moving in circulations to form the so-called “movable walls”, and drives the fluid near each “movable wall” of each layer to move stratifiedly and orderly by allowing multiple layers of “movable walls” arranged on the surface of the object to be resistance-reduced to move stratifiedly and orderly because a relative velocity between the fluid near the boundary face and the boundary face is zero.
The operating environment of the present invention is over ideal and the manual intervention device for realizing the objects are confronted with many difficult problems to be solved. Taking the condition of external flow manner as an example, the fluid frictional resistance always appears with the shape resistance. The conventional moving objects commonly have streamlines, while the circulating path of the device is straight. The stream line can be destroyed by adding a manual intervention device on external surface of a conventional moving object to produce new shape resistance. The manual intervention device is ineffective in reducing the shaped resistance no matter in the condition of external flow manner or in the condition of internal flow manner, except working as a propeller, when the pressure difference between the head and the tail is partially reduced by suction effect, which is similar to water jet propulsion, and thus the loss usually outweighs the gains. Furthermore, in the condition of external flow manner, the operating environment is always quite harsh, while the device seldom has a big resistivity to the unbalanced pressure vertical to the moving direction thereof because the flexible films of the “movable boundary” has no hole and thus the counter-flow area is relatively large. In the practical application, the unbalanced pressure such as a slightly huge wave and slightly large airflow is able to deform the “movable walls” to produce contact frictions even to destroy the operation of the device. If a “caterpillar belt” is used or rolling cylinders are densely arranged to form a stream line, mechanical resistance may be increase and a series of problems can be caused. In the condition of internal flow manner, a large number of rotating components including bearings and rolling cylinders are used, and these rotating components are readily damaged and needs plenty of maintenance. Most of these rotating components are fixed on the original positions, and even the movable flexible films are limited on a certain area, so it is difficult to repair. For example, frequently opening an oil pipeline or a coal water mixture pipeline of hundreds of kilometers long or a long-distance water transferring pipeline to repair various components in fragments, and adding lubricant oil on the bearings are both unacceptable in practical operations. Each movable wall and each layer of movable walls are separated by certain space. In the condition of internal flow manner, many components are provided inside pipes and channels having narrow space and thus effective flow area is further reduced, which further limits the application. Moreover, the internal flow pipe or channel is not always straight and inevitably has many turnings, ascents and descents. If each turning is formed by jointing several straight portions, not only partial loss is not reduced but also new partial resistance is caused; if the fluid therein is accelerated, despite the fact that a part of frictional resistance can be reduced, newly caused partial resistance is so considerable that the internal flow pipe or channel is unfit for the practical application. Many other problems also exist.